She blamed the vandalism on “bored kids” but others are not so sure. At the very least, they say, the attack reflects the current wreckage of her once highly successful political career.

Senior Labour sources have told The Independent they believe Ms Blears, who has a majority of almost 8,000, will struggle to hold on to a once ultra-safe seat in the wake of the expenses scandal. But these are exceptional times for the diminutive former Cabinet minister who stood for the Labour deputy leadership only two years ago.

She has been hit by a bitter backlash in her hometown since it emerged she had not paid capital gains tax of £13,332 on the sale of two flats in London. Writing out a cheque for the amount failed to save her and she resigned as Communities Secretary on the eve of this year’s local election contests.

Since then she has embarked on a dogged street-by-street campaign to appease Salford’s voters. But even her strongest supporters admit it has been an uphill struggle, while Labour chiefs fear she could lose the seat to the Liberal Democrats at the next election.

One former Cabinet colleague told The Independent: “There is some horrendous feedback from Salford. There is a real possibility that Hazel could fail to hold on.”

Senior Labour sources also said she would not be able to rely on reinforcements from national headquarters to help her. They said the anger was still intense over the timing of her resignation in an apparent attempt to destabilise Gordon Brown.

Her name was mentioned three times ? on no occasion flatteringly ? at a meeting of Labour’s ruling National Executive Committee last month. But once she had survived an attempt to deselect her, Ms Blears responded by returning to the pavement politics that made her name.

She has also taken a vow of silence on the national stage and will not be speaking at next month’s Labour conference. Instead, she has become involved in campaigns to save a popular Salford pub from redevelopment, and to prevent the closure of a local newspaper office. She accompanied the Princess Royal on a tour of Salford Royal Hospital, and promoted the work of the town’s SureStart centres.

Her mission, her allies claim, is to meet as many ? if not all ? of her 60,000 constituents by the time of the expected election in May.

A friend said: “She is reminding people why they voted for her in the first place. She is doing the things that will bring people round.”

He said the Labour vote held up relatively well in a council by-election in May at the height of the expenses storm and added: “It would defy all political gravity to lose Salford. It is not a marginal seat. She is determined to get a renewed majority and come back to Westminster with her head held high.”

Steven North, of the Hazel Must Go campaign, said: “She has probably done more canvassing and talking to people in Salford in the last four weeks than in all her years as an MP. But it’s not being well received.”

The campaign has gathered 1,000 signatures calling for her to step down, and plans to hold a public meeting next month where speakers are planned to include the former independent MP Martin Bell. Her opponents will then decide whether to select a candidate to stand against her.

Blears’ allies will suspect political motives as Mr North is a member of the far left Socialist Party, but he insisted the drive to oust her is winning support from all voters.

“If there is a genuine local candidate who has the support of the people of Salford, I think there is a real chance that they would beat Hazel Blears,” he said.